This invention relates to a process for treating radioactive wastes, and more particularly to a process for treating radioactive wastes, where pellets containing the powder of granular ion exchange resin can be shaped.
Various radioactive wastes generated from radioactive material-handling facilities in nuclear power plants, etc. are treated or stored after classification of the individual radioactive waste according to their characteristics. For example, in a power plant utilizing a boiling water type nuclear reactor, a regenerated waste solution containing sodium sulfate as a main component is evaporated and dried into powder by means of a centrifugal film drier, and then the powder shaped into pellets. The pellets are filled in a drum, and the drum is tightly sealed after the filling of asphalt into the drum (Japanese Laid-open Patent Application No. 64699/75).
Used granular ion exchange resin and used filter aid at a high radioactivity level are stored in a slurry state in a tank in a nuclear power plant. When the granular ion exchange resin and the filter aid are stored in the slurry state, a wall of the tank has a risk of corrosion. When the used granular ion exchange resin and filter aid are accumulated only in the tank with the operating time of the nuclear power plant, the tank must be large. Thus, these radioactive solid wastes are filled in drums, and solidified by cement in the drums. However, in such a treatment, it is not possible to fill a large amount of the radioactive solid wastes in the drum, and a large amount of solidified radioactive solid waste are inevitably produced.
To reduce the amount of the solidified wastes, the used granular ion exchange resin is made into powder in a centrifugal film drier in the same manner as for the regenerated waste solution, and the resulting powder is shaped into pellets (U.S. patent application Ser. No. 963,119). However, pellets cannot be obtained only by compressing the powder of granular ion exchange resin.